There is an increasing demand to reduce the sulfur content of hydrocarbonaceous oil to produce products which have very low concentrations of sulfur and are thereby marketable in the ever more demanding marketplace. With the increased environmental emphasis on the requirement for more environmentally friendly transportation fuels, those skilled in the art have sought to find feasible and economical techniques to reduce the sulfur content of hydrocarbonaceous oil to low concentrations.
Traditionally, hydrocarbons containing sulfur have been subjected to a catalytic hydrogenation zone to remove sulfur and produce hydrocarbons having lower concentrations of sulfur. Hydrogenation to remove sulfur is very successful for the removal of the sulfur from hydrocarbons that have sulfur components that are easily accessible to contact with the hydrogenation catalyst. However, the removal of sulfur components which are sterically hindered becomes exceedingly difficult and therefore the removal of sulfur components to a sulfur level below about 100 ppm is very costly by known current hydrotreating techniques. It is also known that a hydrocarbonaceous oil containing sulfur may be subjected to oxygenation to convert the hydrocarbonaceous sulfur compounds to compounds containing sulfur and oxygen, such as sulfoxide or sulfone for example, which have different chemical and physical characteristics which make it possible to isolate or separate the sulfur-bearing compounds from the balance of the original hydrocarbonaceous oil. For example, see a paper presented at the 207.sup.th American Chemical Society Meeting in San Diego, Calif. on Mar. 13-17, 1994 entitled "Oxidative Desulfurization of Liquid Fuels" by Tetsuo Aida et al. The disadvantage to this approach is that the isolated sulfur-bearing compounds are still not useful as a sulfur-free material and therefore the yield of a sulfur-free material from the original hydrocarbonaceous oil is less than desirable and therefore uneconomic.